Liquid level meters measure an amount of liquid in a storage container. For example, in an automotive application, a liquid level meter, e.g., a fuel level sensor, typically measures an amount of fuel in a fuel tank and provides a signal to a fuel gauge of a vehicle.
Existing oil level sensors include a floating magnet that rests on top of oil in an oil pan and changes position based on the changing level of oil in the oil pan. As the float changes position, it operates a reed switch. However, the reed switch gives only an indication of high or low oil level.
Some existing fuel level sensors are subject to oxidative degradation from fuel components. In particular, degraded gasoline accelerates oxidative degradation. Some fuel level sensors have a wiper arm connected to a float. As the float rises with fuel level, the wiper arm contacts a variable resistor, which typically comprises a strip of resistive material, and creates an electrical circuit. Oxidative degradation increases the resistance of the electrical circuit and contributes to failure of the contact between the resistive material and the wiper arm.